A Neighborhood Guide to Chicago Bats

Thursday, October 29, 2015

by Lincoln Park Zoo

in

Conservation Field Diaries

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October 25–31 marks BAT WEEK, a week dedicated to bat awareness and conservation! Why a whole week? Bats need a lot of love these days. In recent years, bat populations have been declining due to a devastating fungal disease called white-nose syndrome.

Big brown bat. Photo by Liam McGuire.

Beyond that, bats are one of the most diverse groups of mammals with more than 1,200 species living around the world. It’s been estimated that bats provide a minimum of $3 billion in services to the agricultural industry in the form of pest control each year. In sum, we need bats!

There are eight species of bats that can be found in the Chicago area, but not much is known about which species live where and how populations are doing in the face of disease and increasing urbanization.

Scientists in Lincoln Park Zoo's Urban Wildlife Institute have bat-monitoring stations set up throughout the city, set to listen in on the calls of Chicago's bats.

To find out more, we have been monitoring bats at forest preserves, golf courses and city parks located from downtown to the far suburbs by recording their ultrasonic echolocation calls. In honor of Bat Week, we’d like to share highlights from some of our favorite bat spots around the city!

Lincoln Park Zoo

A single little brown bat was among the wild species heard around Lincoln Park Zoo. Little brown bat Creative Commons photo by Ann Froschauer/USFWS.

Lincoln Park Zoo was one of our most diverse sites in 2015, boasting seven species, including a single call by a species in the genus Myotis, likely a little brown bat. Although not yet federally listed, little brown bats are one of the species most affected by white-nose syndrome, suffering losses of more than 90% in some caves.

The other six species we recorded flying over the zoo were big brown, eastern red, hoary, silver-haired, evening and tri-colored bats. It’s exciting to see that our zoo provides habitat for all species, big and small!

These West Side neighborhoods are home to the big brown bat, a common, colonial roosting species that ranges across the United States. Big browns do well in urban areas because they can take advantage of human-made structures for roosting: think attics, steeples and belfries. This neighborhood has lots of old buildings, homes and churches as well as large, established trees. Perfect habitat for big browns!

You might be surprised to learn that we recorded moderate bat diversity in downtown Chicago, likely due to its proximity to Lake Michigan. The lake’s coastline provides a linear corridor along which bats can travel, both locally and during spring and fall migration seasons. This site was unique due to the high number of hoary bat calls. The hoary bat is Chicago’s largest bat, and prefers uncluttered, open habitat…such as park areas along the lake. We also detected eastern red bats and silver-haired bats in this area.

After the zoo, Jefferson Park was our next most diverse site, where we detected six species. This northwest-side neighborhood is home to several forest preserves, which are ideal habitat for tree-roosting species like the silver-haired bat.

We recorded several silver-haired bat calls in this area. Silver-haireds appear very dark in color, almost black, with faintly frosted hairs. They are generally solitary and roost in leaf litter, tree cavities or under bark. We also recorded big browns, Eastern reds, evening and tri-colored bats at this site.

That’s a lot of bats, but it only represents results from a few of our sites in 2015. We plan to increase the number of sites next summer to learn more about which factors drive the distribution of bat species in the city.

Learn More

The Bats of Chicago
Just in time for Halloween, biologist Julia Kilgour shares five of the bat species you can find flying over Chicago!

Listening to the Skies
Bats are hard to spot, so zoo scientists listen to the skies to monitor populations in the Chicago area. Urban Wildlife Institute scientist Julia Kilgour shares all the details—including how you can help!

Chicago Wildlife Watch
Help zoo scientists ID more than 1 million photos of Chicago-area wildlife in this fun citizen-science project with Adler Planetarium.